For several months, whenever the Firefox browser opens a Fox News Web page, the browser has been loading pages extremely slowly. Videos take 45 or more seconds to load. The keyboard and mouse become sluggish, locking up for 2-3 seconds at a time. Even after the Web page has finished loading, the keyboard and mouse continue to be sluggish.

I also notice that on the status bar, I see numerous messages about (what I believe to be) tracking programs that are trying to gather information.

These performance problems are specific to the Fox News Web site only.

I have spent a lot of time trying to troubleshoot this problem. I disabled various extensions, for example, but this didn't help. Finally, I just identified and eliminated the performance problem by making the following two configuration changes: